This invention relates to the application of pesticides and herbicides by a spraying process, and more specifically to the in-flight formation and aerial spraying of a multifluid invert emulsion carrying a pesticidal or herbicidal agent.
The use of water-in-oil invert emulsion spray to reduce wind draft is well known to persons associated with aerial agrichemical spraying. In summary, the process involves the making and spraying of a solution consisting of a pesticidal or herbicidal agent, the aqueous and oil phases, and an effective concentration of emulsifying material that promotes the formation of a water-in-oil emulsion whereby said aqueous phase is intimately and finely dispersed in said oil phase.
Various methods and apparatuses have been previously suggested for producing and applying invert emulsions from an aircraft. None, however, have been able to sufficiently control turn-on, cut-off, dosage, and flow rate of the various components to assure uniform application of the solution containing the pesticidal or herbicidal agent. Among the numerous factors contributing to the uniform aerial application of spray over a controlled area, continuity and uniformity of flow of the invert emulsion components are extremely critical; sudden changes in the rheological properties of the invert emulsion can result in excessive drift which may cause irremediable damage to neighboring crops.
The ideal invert emulsion spraying system should produce a clean turn-on and cut-off of the spray, requiring no in-flight adjustment. Ease of operation is also essential to the operator of an airborne system, who must devote his attention to the control of his aircraft. Furthermore, the system itself must be light and have the minimum impact upon aircraft maneuverability.